This application pertains to the art of security systems and more particularly to security systems to prevent pilferage or entry of persons carrying prohibited materials. The invention is particularly applicable to employee plant entry and exiting and will be described with particular reference thereto. However, it will also be appreciated that the invention has broader application such as in airport security, retail sales, or any area in which restricted personnel access is advantageous.
A significant amount of productivity and profitability is lost by businesses each year due to employee pilferage. The traditional way of lessening such pilferage is with security guards working at plant entrance and exit checkpoints. While security guards are of some benefit, they leave substantial possibility for theft. The volume of employees through a checkpoint, especially during shift changes, coupled with an ability to conceal objects, makes it very difficult for security guards to prevent theft.
An earlier generation of theft detection systems was provided in U.S. Pat. No. 3,292,080 entitled "System and Method for Preventing Pilferage by Detection of Magnetic Fields" and U.S. Pat. No. 3,896,372 entitled "Magnetic Sensing Detection System and Method". Both of these patents were developed by the inventor hereof and both disclose systems for preventing pilferage. They utilized a magnet for magnetizing hard ferrous material on the person of the employee. While effective, the systems were limited in the types ferrous materials which were detectable. The systems also provided bottlenecks to traffic flow in high traffic areas or during high traffic periods. This problem was exacerbated when the normal traffic flow was interrupted due to a detected pilferage. Finally, the systems were unidirectional or required expensively duplicative hardware to accomplish employee checks during entry or exit from a plant. Thus while library pilferage and the like has been greatly decreased by my earlier developed systems, such systems were not in use in the manufacturing and warehousing environment.
The present invention contemplates a new and improved security system which overcomes all of the above-referred problems, and others, and provides a system which is more accurate, versatile and economical.